Looks like a portable steam power plant. Probably late 1800s prior to the steam tractors. Pull it to your site with your team and then hook it up for threshing or crushing or sawing or whatever. The arid weather in AZ won't hurt it much. Looks like it has a fine patina of oxidation and it will probably look much the same 100 years from now with no help or shelter. It would take a lot of work and research to put it back in running condition. Front of boiler - gone, piston assy-gone probably missing grates and shakers in the fire box too. I like the ball connection to the front axle. It would gimble and give you some lattitude on where you parked it to work.